DNA testing on the child, who was discovered by a dogwalker in east London earlier this year in below-freezing conditions, has confirmed the link.
The infant girl, who the hospital personnel called Elsa, is connected to a boy and girl who were both abandoned in the same location in 2017 and 2019, respectively, according to the results.
Investigations are still on, and the police have not yet established who their parents are.
When baby Elsa was discovered in Newham, it was believed that she had not been born for more than an hour until a bystander heard her wailing.
At approximately 9:15 p.m. on January 18, the dogwalker found her inside a reusable shopping bag, wrapped in a towel, close to the intersection of High Street South and the Greenway walkway.
They were later commended by authorities for saving the child’s life and kept her warm by covering her with blankets until paramedics came.
The infant was later deemed “safe and well” by the authorities.
A prior court hearing heard that Elsa’s birth cannot yet be officially recorded, nor could a definitive decision about her care be made, as the investigation into her birth is still ongoing.
After an appeal by the three children, an East London Family Court judge has now decided that reporting restrictions might be relaxed to allow the publication of the link between the three youngsters.